Getter for vacuum tubes



April 6, 1943. A.'J. KING I 2,316,127

GETTER FOR VACUUM TUBES Filed Dec. 8, 1941 ATTO NEYS.

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Patented Apr. 6, 1943 GETTER FOR VACUUM TUBES Aden J. King,

Laboratories tion of New York Syracuse, N. Y., assignor to King Inc.,Syracuse, N. Y., a corpora- Application December 8, 1941 serial No;422,079

' 2 Claims. (01. 2'50*-27'.5")

This invention relates to getters employed to' produce high vacuum inso-called vacuum tubes, and relates more particularly to the productionof high vacuum in thermionic tubes, such as radio tubes and the like.

At the present time, these getters consist of a piece of metal to whichis attached the getter material or medium, the piece of metal beingsupported within the glass envelope of the tube and after the tube hasbeen exhausted by mechanical means and sealed, the metal getter isbrought'to a high temperature by the application of high frequencycurrents. The metal is thus heated sufiiciently to vaporize the gettermaterial whereupon the material functions to reduce any gas remaining inthe tube.

The tubes referred to are manufactured in great volume production, mostof the manufacturing process being carried out by automatic machinery.The application of the high frequency current is accomplished byinserting the completed envelope into a coil energized by such current.This heating of the metallic support for the getter material consumes anappreciable amount of energy and time. The getters in common use areusually formed of nickel inasmuch as this metal, in the shape and formnow used, is more efiiciently heated to the desired temperature.However, the melting point of this material is too low to permit the useof certain getter materials which, in themselves, are more effective inproducing the extremely high vacuum necessary for the proper operationof the tube.

This invention has as an object a getter or support for getter materialso constructed and arranged that it will be more effectively andelliciently heated by the induced current from the high frequency coilresulting in an appreciable reduction in the power consumed in raisingit to the required temperature to vaporize the getter material and alsoto reduce the time interval necessary for this operation and which hasthe further advantage that the support may be formed of materials otherthan nickel, such for example as iron or steel, without increasing theconsumption of current in the heating process, and which materials areat the present time more available and at a substantial reduction incost.

Tests conducted have proven that getters embodying my improvedconstruction and formed of steel have more favorable power and timerequirements than the conventional getters now formed of nickel or, ifgetters embodying my invention are made from nickel, there is a decreaseof approximately forty percent in the power input required for heating,as compared with the present form of getter made of nickel. preferhowever to construct the getters of steel as this will permit the use ofmore effective getter materials which, as explained, have not previouslycom into common use because of their high vaporization temperatures.

The invention consists in the novel features and in the combinations andconstructions hereinafter set forth and claimed.

In describing this invention, reference is had to the accompanyingdrawing in which like characters designate corresponding parts in allthe views.

Figure 1 is a view, in elevation, of a radio tube in'which a getter ofmy invention is mounted.

Figure 2 is a perspective view of a getter embodying my invention.

Figure 3 is a top plan view of the structure shown in Figure 2.

Figure 4 is a sectional view taken on line 44, Figure 3.

Figures 5, 6 and 7 are views similar to Figure 2 illustrating slightmodifications of my invention.

Figure 8 is a sectional view taken on line 8-8, Figure 7.

Figure 9 is a top plan view illustrating another modification.

In accordance with my invention, the getter consists of a support in theform of a closed band Ill formed from thin sheet metal. The sheet metal,from which the band is formed, is relatively thin, being in theneighborhood of .005 to .010 of an inch in thickness, whereby thethickness A, Figure 4, is less than the width of the band indicated atB. This band may be of any desired shape, such as circular, elliptical,or rectangular.

The getter material or medium, indicated at H, is attached to the bandin any suitable manner as for example forming a small depression or cutin the band and pressing the getter material therein. The band isprovided with a support member in the nature of a rod l2 Welded orotherwise secured at one end to the band l0 and being fixedly secured atits opposite end to the supporting structure within the tube, asillustrated in Figure 1. The rod I2 is adopted to position the band withthe axis thereof extending parallel to the axis of the tube.

In use, the current from the high frequency induction coil quickly heatsthe band to a temperature for vaporizing the getter material H. In orderto heat the getter material I I more rapidly and with less powerconsumption, the band may be provided with a portion l3 of reduced crosssectional area. As shown in Figure 5, this area is produced by cuttingaway a portion of the band, or cutting a notch therein. In Figure 6, theband is cut away adjacent both side edges to form the reduced portion l3and, in Figure 9, the band is partially formed by a thinner portion Hi,the portion l4 being only a fraction of the thickness of the materialfrom which the main portion is formed. In each instance, the gettermaterial H is arranged in or on the portion of reduced cross sectionalarea.

I prefer the structures shown in Figures 7 and I 8. The reduced area I3is formed by a pair of spaced cuts extending inwardly from one side ofthe band, the material between the cuts however is not removed as inFigure 5, but is folded downwardly in the form of a flap or tab'l5 toprevent the spattering or loss of getter material and, at the same time,to direct the vaporized getter material toward the base of the tube andaway from the metal elements in the upper part of the tube.

What I claim is:

1. An individually fiashable vacuum tube getter comprising a closed bandopen at each end and formed from thin sheet metal and being of greaterwidth than thickness in cross section, said band having a portion ofreduced cross sectional area and a quantity of getter material attachedto the reduced portion of said band.

2. An individually flashable vacuum tube getter comprising a closed bandopen at each end and formed from thin sheet material and being ofgreater width than thickness in cross section, said band being cut fromone edge inwardly at spaced intervals to form a tab, said tab being bentout of the plane of the band to form a portiono-f the band of reducedcross sectional area, a quantity of getter material attached to thereduced portion of said band and said integral Jtab being folded oversaid material.

- ADEN J'. KING.

